Q-series compatibilizers

Linear low-density polyethylene (LLDPE) and PS resins were the same as described previously (Chapter 21). The various block copolymers that were used as compatibilizers have also been described (I). A series of crystalline copolymers (Q series) was prepared by hydrogenation of diblock and triblock copolymers of styrene and butadiene [styrene-hydrogenated butadiene (SEB) and styrene-hydrogenated butadiene—styrene (SEBS)J (1). Triblock copolymers of styrene and butadiene [styrene-butadiene-styrene (SBS)] and a noncrystalline hydrogenated block copolymer (SEBS) (Kraton) were supplied by Shell Chemical Co. Diblock copolymers of styrene and butadiene [styrene-butadiene (SB) (Vector)] were obtained from Dexco Polymers. The characteristics of the resins are given in Table I. 

The general shape of the stress-strain curve is the same for all the blends with Q-series and Kraton compatibilizers. This shape is described by two tangent lines drawn from the initial elastic region and the plastic region, respectively. The intersection of the lines is defined as the yield point and is described by a yield stress (ay) and an apparent yield strain (ey). The stress (a) and strain (e) in the plastic region are related by... 

---